The 40G TWDM-PON (Time Wavelength Division Multiplexed and Passive Optical Network) has now been primarily determined by a standardization organization as a standard architecture of the NG-PON2 (Next Generation Passive Optical Network 2, next generation passive optical network 2). One of key technologies of the 40G TWDM PON is to implement a 4×10 Gbps OLT (Optical Line Terminal, optical line terminal) transmitter optical module. Currently, a relatively common solution is to dispose 4 TOSAs (Transmitter Optical Subassembly, transmitter optical subassembly) and 4 ROSAs (Receiver Optical Sub-assembly, receiver optical subassembly) together in one module to form a 40G TWDM PON module, as shown in FIG. 1. It can be learned according to a structure described in FIG. 1 that both the transmitter optical subassemblies and the receiver optical subassemblies are packaged with four in one at a time to form a transmitter component with a rate of 40 Gbps. For both a user and a supplier, this solution has gone beyond demands, which consequently causes a large quantity of wasted resources.